The present invention relates to flat speaker devices of type adapted to be embedded in flat wall surfaces or the like for use, and more particularly to a flat speaker device which has an excellent aesthetic appearance and can produce an excellent acoustic effect.
A flat speaker of total-drive type in which a plurality of magnets are juxtaposed at regular intervals on a flat plate, each of said magnets being covered with an inverted-U shaped (projection) vibration structure or diaphragm, and the diaphragm is vibrated to obtain a reproduced sound has been known (for example, as disclosed in U.S. Pat. No. 4,228,327 and Japanese Patent No. 1,172,546).
The total-drive type flat speaker possesses the characteristic whereby the thickness thereof may be materially reduced as compared with a generally used so-called concentrated-drive type speaker having a voice coil. A variety of modes of installation and methods of use have been studied by making use of the aforesaid characteristic. For example, if the flat speaker is embedded flush into a wall surface so as to form a part of the wall surface, an acoustic room can be constituted wherein the speaker is not projecting out from the wall surface, and excellent exterior appearance is obtained. In addition, if a number of flat speakers are embedded in a wall surface, varied acoustic effects may be obtained. It is very difficult for a conventional type speaker to be used in such a manner because it has a greater front-to-back depth necessitating a large cavity to be provided in the wall.
Furthermore, the larger the speaker, the better its performance in the low sound region, but in an ordinary system there is a disadvantage in that the installation space increases.